Slack adjuster



Jan. 8, 1957 c. E. TACK sLAcK ADJUSTER Filed June 5, 1952 g ZZ 1 N VEA' TGR. a/zf 5. kZad/17;

United States Patent() "ice 2,776,586 sL/ACK Asarusfivun Carlv Tack, .Ghicagoa illl, assiguor., to American `Steel Foundries, Ghicagm-:Illtya corporationfof New-.Jersey Applicaeunjunes, 19fsz,seri1N0. 291,498

`3i Climsti (Gl: Mh-522) This' invention relates'do. slack.` adjustersiandmore: particularly to a: novel..` slacle adjuster normally utilized toi coxrxponsate-` for:4 wear brake riggingA of railway cai LIl'llt'ks.

Assl well.t known A to.: those. `familiar` with.y thebrake: riggingart, a-hrakerllever isigenerally adaptedtmcarry a zbt-'akez shoe which, turnyfisl. operative to engage. the; wheel.trveadffoftafnrelated wheeltafnd `axle.assembly. In `:afwell-known `type of4 brakef rigging for railway car truoksg. an brake nlever-.brake shoe. assembly is! disposed ion `eacht sident. an .associated wheel, and.y connecting t means,

as.=,aisiugle strap paralleling. thenwheelsor. multiplef strapsf stradd'ling,th'ewheehl oiier'support for theI lower endofsthe:rel-atedrbrakelleversa A11-example.ofr this -type `ofibrake.riggiuglis `the patentitoSimanek-.No 1,969,159,

issued August-7,. 193.4. Inisuchaconstruction. a.slack adg'uster consistsaomeans forreducingV theetfective lengthT t of. said. straps-in order` to, accommodate. wheel: and shoe wear.

Itis..a general object .of the inventioruto devisea novel slack adjuster constructed and arrangedtoprevent dirt,

. moisture. and other` foreignmatterA from,4 fouling threaded;

members ttherein... y

A.niore specifictobject ofthe invention.isto devisea novel,slack adjuster. wherein telescopingmernbers. are in sealed engagement and'. form :a completely; enclosed'` cyl- `inder.within which is .dis`posed=screw thread means.

Another specitic object ofth'einvention is to devise. a

,novei springlock in combinationwith. the above Ide- .scribedslaclt` adjusterthere'by preventing accidental 4ads justnent ofsaidfdevic'e.

"in-g and istiriterrupte'clI intermediate4 its" endsby the slot 8'; separating"tire-cylindrical-portion'6, at apointcentrally; of' and' directly'above 'the base'piortion"4,\v into` segvments Sand 7: The cy-lindr'icz'rl portion 6` is formed and ariangedeto deiiue-apassageway1 10?; preferably of cire eular'fori'n in` cross'section, disposed to communicate with tlieslot 8-on--opposedsidesfthereof. It is to 1benotedl lthabthepassageway` 10 is-openI fait one; end asf at i12;-v and f at; its other end'- is substantiallyn closed by 'then wall` 14 termed Iintegrally-with-the cylnder'- 6". A liolefor/"aperture 16 is formed centrally of the end wall and may be aligned with the longitudinal axis of the passageway 10.

aFiatteneteedf Jan; 8,4 y1957 within the f passageway' 10V in :such a manner as to cirycuni,ferentiaully abut Vthe innersurface ofthe passageway andi extendfthrough. the separating slot 8, thereby interconnecting-thesegtnents 5 and 7- of the passageway 10. The. bushing 1'8-istightly fitted within the passageway 10, that is, a metal-to.metal t, thereby assuring a sealed connection therebetween. The lbushing 18 may be xedly secured mits-assembledA position in any convenient'manner, .such iasy by weldingrto the t cylinder. `6 -as yatf20.-

In a4 preferred.v embodiment .of.V thelinvention, a;forked brake lever is employed. and is partially shown'atlZfin Figure 3. Atthelower extremities of the forked lever 22,.coaxial holes24-.withlbushinginserts 26 areeprovided. Asepa-rate yoke .28 totH Ushaped form .is Adisposed .within therslot Sadjacentto. and separatefrom brake lever 22 with its fopen end directed 4downwardly 'embracing a -portion.of the bushing 18.Y At the lower end of the extremities.of1theyolie,\piu.` andtholeconnection as at 30 Vis made to the baseportion4fof the housing; 2. Thus the yokezisasecurely attached to .thelhousiug 2; Onopp'osite .sides ofthe;` ypke;23,-.andipreferablyainr a horizontal plane passingirthroughfthe.longitudinal axis of the passageway 10i,l .circular .outwardly directed bosses32 are presented. Eachibossllis pivotallyreceivedby the bushed hole 24 of the related forkoftheibrake lever22. Thus, pivotal connection' isprovidedfbetweenthe housing' 2 and brake leverportion ZZ-of the Abrake rigging.

The adiusting. s'crew-r 36. comprises a malel threaded ,cylindrical body` portion 38-andv a lug 4ilpositioned ou .one end ofthe body portion inalignment with the longitudinal axis ofi said?body=portion4 The aperture 16 ofthe end 1 wall' 14 oierscomplementary reception .for the lug ,40; of theA screw 36,. said lug extending.` through said aperture-,andirigidly connected to theend wall by any `suitable meansvsueh as-weldingat 41. Thus the screw is' rigidlypositioned-within the passageway 1) ofthe `housingl, saidpassagewayandscrewhaving a. common longitudinal axis-.-

A bodyor-` sleeve 42,:of hollow cylindrical form in Grossi-section.havingiyan opening 43at oneend and an integrally formedswallf 44 f at the' other end ispreferably `teleseopedwithin thelbushingfl anddisposed to surround the=screwf36- Asnoted, theasleeve 42. presents the cylindrical-` recess: 46, .the diameterV of which is greater than thezdiameter of thezscrew-h thus. providing ,radial clearance for the. screw .duringthe relative movement therebe- `tween hereinafter. described: Adjacent theopen end 43 Vofthe lbodyf`42, .the'recess 46 "is -reduced in diameter and presents the female screw threads formed' to complement and engagethe mentionedrma-1e threads onith'e screw 36. Thiswlconstruction provideslfor` relative controlled movement .betweennthescrew 36'fof the-.housing 2 and ,the body 42, upon relative `rotation r of vsa'idbody.

. It isftofb'e.notedthatfthe sleeveior body 42 circumferentially abuts the inside surfacejof the bushing 18, that isf-tliesleeve-"is snuglyftted within the bushing. The clearance' between they intertting bushing 13 and the sleeve 42 approachesV a substantially rnetal-to-nietal t, hence a'ccomm'od'atingrelative"rotation betweentheparts, but being operative' to'substantally seal the passageway 10, thus preventingdirt,I moisture or other foreign matter from enteringrrtherein and clogging the screw threads. This feature is particularly desirable in railway operation v where the brakeriggingis.carried.externally on the trucks thereby freezing the sleeve within the housing, the external connection can be broken and the adjuster dismantled and repaired without breaking the housing 2.

The wall 44 of the body 42 presents the solid cylindrical boss 50 which, in the preferred embodiment, is loosely received by the hole 52 of the partially shown brake strap 54. Centrally of the boss 50 and integral therewith, a lug 56, preferably of square cross section is formed to extend outboardly of the strap 54 and to be received by a complementary hole of an associated adjusting nut 5S. Aligned apertures 60 and 62 are presented by the lug 56 and nut 58, respectively, and provide for pin connection of the nut to the lug.

The adjusting nut 58 of the preferred embodiment consists of two portions, one of which is the adjusting portion 64 characterized by its hexagon cross section which is adapted to mate with a wrench or other conventional tool for rotation of said nut. A locking portion 66 is arranged on the opposite end of said nut and is characterized in the preferred embodiment by its octagon cross section disposed intermediate spaced parallel retaining anges 67 and 69 peripherally disposed on said nut. It is to be noted that any polygon formation of the adjusting portion or locking portion of the nut 58 would satisfy the requirements of the invention.

Spring lock means 70 are provided to prevent accidental rotation of the nut which would result in a variation of the slack position. As best seen in Figure 3, the vertically aligned holes 72 and 74 are provided in the related strap 54 on each side of the nut 58. It is to be noted that the distance A from the center of the holes '72 and 74 to the vertical axis passing through the center of the adjusting nuts as seen in Figure 3, is equal to or less than the perpendicular distance B from the center of the nut 58 to a given at on the octagon locking portion 66. The spring lock means 70 consists of a U-shaped wire spring having the leg portions 76 and 78 disposed within the holes 72 and 74, respectively, of the strap 54. The connecting portion 80 of the spring lock 70 is positioned intermediate the spaced retaining flanges 67 and 69 and abutting the octagon portion of the nut 58. Due to the relation between the mentioned distances A and B, the connecting portion 80 is distorted from its normal shape and resiliently abuts a related at of said Octagon portion. The pressure exerted by said spring lock 70 maintains the nut in a given position, thus preventing the mentioned accidental rotation. However, the exibility of the spring lock 70 accommodates rotation of the nut when a sufficient twisting moment is applied thereto, as would be the case during manual adjustment of the slack device. The strap 54 may be maintained in level position by a guide or support bar (not shown) which is in turn secured to a pair of ears 9 formed on the cylindrical portion 6 of the base 4.

In operation, rotation of the nut S8 concurrently rotates the body or sleeve 42, which in turn, varies the relative position of said body on the screw 36. This action varies the relative position between the brake lever 22 and the strap 54, hence accommodating wear on the braking surfaces.

The invention has been illustrated as applied to a brake lever-single strapped brakerigging assembly, but, as would be obvious to those skilled in the art, only slight modification would be required to apply the invention to a multiple strap brake assembly or to other portions of the brake rigging, such as, for example, pull rods and it is to be understood that theinvention as claimed comprehends such applications.

I claim:

1. In a slack adjuster arrangement, a base having spaced coaxial bores and an end wall closing the outer end of one of said bores, a cylindrical bushing extending between and secured within said bores, a yoke having spaced arms straddling the medial portion of said bushing, said arms being secured at their ends to said base, coaxial trunnions projecting from opposite sides vof said yoke, a brake lever having a bifurcated end straddling said yoke and provided with bearing apertures to receive said trunnions, a screw coaxially positioned within said bushing and having one end thereof xed to said end wall, an internally threaded adjustment sleeve having its inner end threaded onto said screw and snugly sildably engaged within said bushing, the outer end of said sleeve being closed by an end wall having a cylindrical boss projecting outwardly therefrom coaxial with the sleeve, a lug on the outer end of said boss, a nut secured to said lug, and a brake strap having a bearing portion journaled on said boss and engaged between the sleeve end wall and said nut.

2. In a slack adjuster arrangement, a base having spaced coaxial bores and an end wall closing the outer end of one of said bores, a cylindrical bushing extending between and secured within said bores, a yoke having spaced arms straddling the medial portion of said bushing and secured at their ends to said base, coaxial trunnions projecting from opposite sides of said yoke, a brake lever having a bifurcated end straddling said yoke and provided with bearing apertures to receive said trunnions, a screw coaxially positioned within said bushing and having one end thereof fixed to said end wall, an internally threaded adjustment sleeve having its inner end threaded onto said screw and snugly slidably engaged within said bushing, the outer end of said sleeve being closed by an end wall having a cylindrical boss projecting outwardly therefrom coaxial with the sleeve, a lug on the outer end of said boss, a nut secured to said lug, a brake strap having a bearing portion journaled on said boss and engaged between the sleeve end wall and said nut, said nut having flat surfaces, and resilient means on said brake strap in abutting engagement with one of the at surfaces on said nut to yieldably resist rotational movement of said sleeve.

3. In a slack adjuster for a related railway brake mechanism, a housing having a slot extending transversely thereof, a passageway defined within said housing and having portions communicating with said slot on both sides thereof, a cylindrical bushing sleeved within said passageway extending between said portions and xedly secured to said housing, a wall on said housing at one end of said passageway closing same, a screw abutting said wall and nonrotatably connected thereto and axially aligned with said cylindrical bushing, a yoke disposed within said slot and having arms embracing said bushing and extending therebelow to xedly engage said housing, spaced coaxial trunnions on said yoke to be journaled on a brake lever, a sleeve having an open end receiving said screw and in threaded engagement therewith, said sleeve having a closed end to seal the end of said passageway, said closed end having a journal portion coaxial with said sleeve to engage a brake strap, and means on the closed end of said sleeve to adjust the position of said sleeve relatively to said housing.

References Cited in the le of this patent UNITED STATES PATENTS Re. 19,745 Baselt Nov. 5, 1935 1,294,424 Dearborn Feb. 18, 1919 1,296,835 Monsen Mar. 11, 1919 1,469,571 Adreon et al Oct. 2, 1923 1,877,367 Seppmann Sept. 13, 1932 1,907,510 Bushman May 9, 1933 2,104,787 Blomberg Jan. 1l, 1938 2,112,817 Schwentler Mar. 29, 1938 2,231,150 Blomberg Feb. 11, 1941 2,425,979 Bachman Aug. 19, 1947 

